The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Users may grant access to their user accounts by providing credentials related to those accounts. However, once such credentials are shared, in many cases they may not be securely revoked. For example, once an account number is shared with a service provider, that account number cannot then be robustly retracted from the knowledge of that service provider.